A miniature-scale refrigeration system suitable for electronics cooling applications was developed and experimentally investigated. A detailed review of the literature on refrigeration systems and system simulation models for application to electronics cooling is also provided. Experimental results obtained with the prototype system demonstrate its feasibility for use in cooling compact electronic devices. The cooling capacity of the system investigated varied from 121 to 268 W, with a COP of 2.8 to 4.7, at pressure ratios of 1.9 to 3.2. The effectiveness of the condenser ranged from 59 to 77%, while a thermal resistance of 0.60 and 0.77 ºC-cm 2 /W was achieved at the evaporator. The evaporator-heat spreader thermal resistance is defined as the ratio of the temperature difference between the chip surface and the refrigerant evaporator to the evaporator heat transfer rate.The overall system thermal resistance, defined as the ratio of the temperature difference between the chip surface and the condenser air inlet, is of 0.04 to 0.18 ºC-cm 2 /W. An overall second-law efficiency ranging from 33 and 52% was obtained, using a commercially available small-scale compressor. The measured overall isentropic efficiency was between 40 and 60%.Index Terms-Miniature-scale refrigeration system, electronics cooling, small-scale compressor, second-law efficiency,

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Traveling-wave electrohydrodynamic (EHD) micropumps can be incorporated into the package of an integrated circuit chip to provide active cooling. They can also be used for fluid delivery in microdevices. The pump operates in the presence of a thermal gradient through the fluid layer such that a gradient in electrical conductivity is established allowing ions to be induced. These ions are driven by a traveling electric field. Such a traveling electric field can be realized in practice only via discrete electrodes upon which the required voltages are imposed. The impact of using discrete electrodes to create the traveling wave on the flow rates generated is explored through numerical modeling. The change in performance from an ideal sinusoidal voltage boundary condition is quantified. The model is used to explore the widths of electrodes and the intervening isolation regions that lead to optimized pumping. The influence of the choice of working fluid on the performance of the pump is determined using an analytical model.

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